abc's bob woodruff has the story. >> reporter: 32-year-old gabriel posey, a staff sergeant in the army, just returned from the sands of afghanistan. but now here, in los angeles, he's about to get a huge surprise. what he knows is that he's been matched up with a mentor to help him get a start in the field he's dreamed about much of his life, screen writing. what he doesn't know is that his mentor is one of the biggest names in hollywood. >> your brothers were killed in combat. >> this is one of the great things about people in the military, they're good at solving problems. those people are worth their weight in precious metals. >> what will be the number one thing you'll tell him about getting into the film industry? >> okay. you have got to say i know who i am, i know what my kills are, and i'm in this for the long haul. perseverance. it all comes down to that. >> reporter: i told gabriel his mentor wasn't well known. just someone with connections. i lied. i'm going to show you who this is. i think you'll be very happy. >> oh! wow! no way. i love tom hanks. >> gabriel, how are you?